In recent years, composites of silver microparticles and organic compounds have been attracting much attention as materials for forming the electrodes or circuit patterns or the like of electronic devices. In Patent Document 1, silver particles with an average particle size of not more than 20 nm and having an organic compound containing one or more unsaturated bonds within each molecule, and specifically oleylamine, provided on the surface of the particles are disclosed as an ink material for an inkjet method. In Patent Document 2, a silver colloidal solution containing silver-based particles in which a coating layer composed of polyvinylpyrrolidone, polyallylamine or polyethyleneimine is provided on the surface of silver particles having an average particle size of not more than 10 nm is disclosed as an ink material for an inkjet printer, but use of this silver colloidal solution for formation of a conductive member is not described.